Dizziness and vertigo are common symptoms reported to physicians. Technically, dizziness is defined as a feeling of lightheadedness whereas vertigo also includes the feeling of spinning. Because there are a number of different causes of dizziness or vertigo, such as visual deficits, neurological disorders, and cardiovascular disorders, among others, it can be difficult to diagnose the cause of the symptoms, which can lead to frustration and ineffective treatments being applied.
When frequent episodes of dizziness or vertigo are linked to changes in head position, however, a vestibular disorder may be suspected. Peripheral vestibular disorders are essentially a dysfunction of the balance organs of the inner ear. Central vestibular disorders, on the other hand, are disorders of the portions of central nervous system that assist with balance and spatial information.
The human body maintains balance using sensory input from the eyes, sense of touch in feet, torso, and spine, and the vestibular system in the inner ear. When there are mixed signals from these different sensory systems, the body can usually compensate. When there is a vestibular disorder, however, the body can no longer adapt and dizziness or vertigo result. Some causes of vestibular disorders include acoustic neuromas, autoimmune inner ear diseases, loose debris collecting in the inner ear sensor, head injury, degeneration of inner ear cells secondary to aging, an abnormal skin growth behind the eardrum or bone growth in the middle ear, viral inflammations of the inner ear, Meniere's disease, migraines, exposure to certain drugs or chemicals and vascular compression of the vestibular nerve, among other things.
The vestibular system is interconnected with the visual system in the human body. When the head is moved, signals are sent via the nervous system to the eye muscles so that good balance can be maintained and so that objects can stay steady in your field of vision while your head moves, also known as gaze stability. This feedback loop is known as the vestibulo-ocular reflex (“VOR”). Many tests for vestibular function leverage the VOR to identify abnormal responses when the patient's head is moved. In one such test, the patient wears specially designed goggles with cameras that focus on each eye while the eyes are in darkness inside the goggles and which are able to show the patient's eyes on a display to help determine whether a given response to the head movement is normal or indicates a problem.
In a typical diagnosis routine, a patient will put on a pair of these specially designed goggles and the clinician will have the patient look left and right and up and down with their eyes only. The clinician may also gently shake the patient's head up and down for a certain number of repetitions. Another test is to have the patient seated with his or her legs stretched out in front of them and the clinician has the patient recline with their head at a forty-five degree rotation to one side, depending on which side of the vestibular system is being tested. Based on the movements of the eyes, as shown in real-time or recorded by the cameras, the clinician is able to rule out certain disease states and possibly diagnose the source of the patient's symptoms.
Once a diagnosis has been made, a treatment regime is determined. One possible treatment involves the use of virtual reality goggles. For example, the patient will don the goggles and see either a static picture of a busy background, such as a checkerboard, or they will see a typical virtual reality moving scene such as being in a supermarket and looking around to see different products on the shelves and people walking by. The patient may be directed to view this scene for a certain amount of time or directed to interact with the environment with the goal of improving the patient's ability to tolerate more complicated and busy environments in a controlled fashion.
In order to test and treat a patient's vestibular function, specialized equipment that is either immobile or cannot easily be taken to a patient home or remote site was the only equipment available to a given clinician. What is needed is a mobile assembly or device that has interchangeable components to minimize weight and increase ease of use, transportability, and accessibility for both the clinician and the patient.